Insulin

Insulin
is a
hormone
produced by specialized cells in the pancreas. Secreted into the
bloodstream at each meal, insulin helps the body use and store
glucose
(sugar) produced during the digestion of food. In people with
diabetes
, the pancreas either does not produce enough insulin or the body cannot
use the insulin that is produced in an efficient manner.

Treatment for diabetes requires the delivery of insulin into the
bloodstream by either an insulin pen, needle and syringe, or pump. An
insulin
pen is a device that looks like a pen but contains an insulin cartridge.
Both the syringe and pen methods require injection of the insulin into the
arm, thigh, or abdomen. Pump therapy, however, continuously administers
insulin according to a programmed plan unique to the pump wearer. Several
types of insulin exist, and they differ in when the insulin begins working
after it is injected, when the insulin is working hardest, and how long
the insulin lasts in the body.

Insulin release and glucose
absorption
depend on a number of factors, including the glycemic index of food and
the co-ingestion of
fat
and
protein
. Consumption of high-glycemic foods causes
hyperglycemia
which results in the release of too much insulin. On the other hand,
low-glycemic foods or the ingestion of fat and protein in a meal provide
steady glucose absorption and release of insulin.

Exercise lowers blood glucose levels and increases the amount of insulin
in the bloodstream, along with improving the body's use of insulin.
A balance must exist between the sugar used for
energy
, the sugar available from food, and the insulin used in lowering blood
sugar. Consequently, changes may have to be made to insulin, or food
intake, or both, prior to and after exercise.